The present invention relates to image-based document processing systems, and is particularly directed to a method of operating an image-based document processing system, such as an image-based check processing system, and an apparatus therefor.
A typical image-based check processing system includes a check processing transport which has a document track and a number of check processing modules positioned along the document track for performing specific document processing operations on document items including checks moving downstream along the document track. Each check processing module includes a number of hardware devices contained within the check processing module during operation of the check processing transport. The check processing system also includes a transport processor which executes a transport application program which is stored in memory to control operation of the hardware devices contained within the check processing modules positioned along the document track and thereby to control operation of the check processing transport.
More specifically, the check processing transport includes a hopper module into which a stack of document items are placed. A document feeder module adjacent the hopper module selectively feeds or drives each document item from the stack of document items in the hopper module to transport the document item past an imaging camera of an image capture module. The imaging camera captures an image of the document item. The document item moves downstream along the document track to sorting pockets of a pocket module located at the end of the document track. The pockets receive document items which have been sorted in accordance with the transport application program.
In some known check processing transports, the imaging camera lies on one side of the document track and a movable reference surface lies on the other side of the document track facing the imaging camera. The reference surface has a black surface portion and a white surface portion and is movable between one position in which only the black surface portion faces the imaging camera and another position in which only the white surface portion faces the imaging camera. The black surface portion of the reference surface faces the imaging camera during operation of the imaging camera. The sharp contrast between the dark, black surface portion of the reference surface and the relatively light background of a document item allows the leading edge of the document item to be accurately detected. The white surface portion of the reference surface faces the imaging camera during calibration of the imaging camera. The white surface portion of the reference surface is usually entirely white to allow a complete calibration of the imaging camera to be carried out.
In some other known check processing transports, the imaging camera lies on one side of the document track and a stationary reference surface lies on the other side of the document track facing the imaging camera. The stationary reference surface usually has a white surface portion and a number of black markings contained throughout the white surface portion. The white surface portion and the black markings face the imaging camera and are always in the same position relative to the imaging camera. The black markings allow the edges of a document item to be detected, while the white surface portion allows the imaging camera to be calibrated.
Although using a known movable reference surface with black and white surface portions allows a complete calibration of an imaging camera in a check processing transport to be carried out, a drawback is that mechanical components are needed to move a movable reference surface between different positions. These mechanical components need to be serviced regularly to maintain their proper operation. Also, although using a known stationary reference surface with black markings in a white surface portion does not require use of mechanical components, a drawback is that a complete calibration of an imaging camera of a check processing transport is unable to be carried out. Accordingly, it would be desirable to provide a stationary reference surface which allows an imaging camera of a check processing transport to be completely calibrated.